This invention relates generally to wind turbines, and more particularly to methods and apparatus for operating the wind turbines with over-temperature conditions on wind turbine control motors.
Recently, wind turbines have received increased attention as an environmentally safe and relatively inexpensive alternative energy source. With this growing interest, considerable efforts have been made to develop wind turbines that are reliable and efficient.
Generally, a wind turbine includes a rotor having multiple blades. The rotor is mounted on a housing or nacelle, which is positioned on top of a truss or tubular tower. Utility grade wind turbines (i.e., wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., 50 or more meters in diameter). Blades on these rotors transform wind energy into a rotational torque or force that drives one or more generators, rotationally coupled to the rotor through a gearbox or directly coupled to the rotor. The gearbox, when present, steps up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert mechanical energy to electrical energy. The electrical energy may be sent directly or through electrical converters into a utility grid.
Up until the recent past, control systems for wind turbines often initiated turbine trips or shutdown sequences as a simple response to faults or abnormal conditions. As wind turbines comprise a greater segment of the total power fed into the utility grid, the reliability and continuity of power from the wind turbines become increasingly important to the continuity of operation on the grid. Further, the continuity of operation of wind turbines becomes a more significant economic factor to windfarm operators and utility operators. More complex responses to the faults or abnormal conditions may be devised that might provide for non-interrupted wind turbine output. Accordingly, it may be desirable to provide operating methods and control features that provide for continuity of wind turbine operation during fault or abnormal conditions.